Telephone-transmitter



S. C. PORTER.

TELEPHONE TRANSMiTTER.

APPLICATION FILED APR. 22. 1918.

Patented June 1, 1920.

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I IIVI/ENTOR I ATTORNEY -STE1N C. PORTER, 0F BROOKLYN, NEW YORK,ASSIGNOR T0 PORTEHONE 602:;0RATION, OF NEW YORK, N. Y., A CORPOTION OFNEW Y r.

TELEPHONE-T 1';

Application filed April 22,

To all whom it may concern:

Be it known that-I, S'rEfiHEN C. PORTER, a citizen of the United States,residing at the borough of Brooklyn, city of New York, in the county ofKings and State of'New York, have invented certain new and usefulImprovements in Telephone-Transmitters, of which the following is aspecification.

My invention relates to telephone transmitters which are to be used inplaces where the extraneous noises make the use of the ordinarytransmitter impracticable, such as in aeroplanes, hydroplanes, in thepresence of gun fire and the like, and it is my object to produce asmall, portable transmitter which will operate under the most adverseconditions.

As is well known the pilot and observer in an aeroplane have heretoforebeen unable to communicate with one another except by signals while inthe air by reason of the noise of the engine and propeller andthe rushof air through the planes. It is necessary for these two to, have thefreest communication if the best results are to be obtained, especiallyin photographic work and in instructing pupils. Heretofore verbalcommunications had to be made before or after flights and signalsdepended upon while in the air. Continued use of my invention has shownthat the two can freely converse while in the air but at the same timethe sound of the engine has not been sufliciently shut out to preventthe pilots hearing whether or not it is running regularly. v

In the drawing, Figure 1 is a sectional, view of my improvedtransmitter; Fig. 2 a face view of the face plate of the case and Fig. 3a face view of the face plate of the outer cover.

1 My improved transmitter consists of a microphone having a case 1,diaphragm' 2, carbon back 3, carbon grains 4 and opening 5 in the casethrough which sound reaches the diaphragm. Wires a and I) lead from thecase to make the usual connections. The microphone itself forms no partof my invention as any desired type may be use To carry out my inventionthe microphone is tightly packed in sound deadening material 6. Inpractice this consists in tightly winding the microphone case withstrips of woolen felt completely inclosing it Specification of lettersPatent.

. the case.

smrrnna.

191a. Serial no. 229,887.

in multiple la ers, including the opening 5.

. Patented June E, 192th In this way t e alternate'compr'esslon and Irarefaction of the air due to gun fire is prevented from reaching thediaphragm'and it is p rote cted from breakage but all noises ongmatingat a distance are effectually dampened before they reach the diaphragm.At the same time sounds originating close to the mouth piece will passto and afiect the diaphragm.

The wrapped microphone is then placed in.a case 7 the face plate 8 ofwhich, opposite the opening 5 is preferably, but-not necessarily,perforated at 9. This face plate may be integral with or separate fromthe case. These perforations do not come opposite the opening 5-but areplaced away from the center as shown in Fig. 2.

In order that the intensity of sound reaching the diaphragm may becontrolled the apertures in the face plate 8 are elongated slots and asecond plate 8' like the front plate 8 is revolubly secured against theplate 8 and is provided with a handle 18 extendin through a slot in theside of i moving this handle 18 the plate 8' is rotated and theapertures in the front plate 8 and the plate 8 may be brought more orless into register thereby controlling the effective size of the soundpassages thereby permitting the operator to adjust the transmitter tovarying conditions.

A, flexible, soft rubber mouth piece 15 is then placed on the cover 10and has the inwardly rolled edge 16 and the inner lip 17 which lipspreads over the edge of the face plate 11, directing the'sound wavestoward the apertures in the cover plate. The rubber mouth piece issecured to the transmitter by gripping its edge between the outside ofthe cover 10 and the inside of the back cap 13 as shown in Fig. 1.

In use the rubber mouth piece is firmly I spoken directly into thechamber within the held againstithe mouth and the words are mouth piece.The sound waves pass through the openings 12 and 9, through the sounddeadening material 6 and throu the microphone opening 5 impinging finafion the diaphragm and vibrating it.

By using sound deadening material around the microphone the effect ofextraneous noises isreduced to a minimum and speech is not interferedwith The back cap and its packing prevent sound waves impinging upon theback of the case 7 and protect the microphone from interference on itsmost exposed side. The air space between the inner lip 17 and the sidewall of the soft rubber mouth piece 15 aids in shutting out side sounds.

With my transmitter conversation may be carried on in aeroplanes, undergun fire and under the most disadvantageous extraneous conditions ofnoise.

I claim p v 1. A telephone transmitter comprising a microphonecaseprovided with an opening, a microphone in said case and a wrappingtherefor completely inclosing the same of sound deadening material.

2. A telephone transmitter comprising a microphone case provided with anopening, a microphone in said case, a wrapping therefor completelyinclosing the same of sound deadening material and an outer casesurrounding the microphone and deadening material.

3. A telephone transmitter comprising a microphone having anopening, awrappin therefor completely inclosing the same of sound deadeningmaterial and an outer case having a face plate provided withperforations opposite to the microphone opening.

v4:. A telephone transmitter comprising amicrophone having an opening, awrappin therefor completely inclosing the same 0 sound deadeningmaterial, an outer case having a face plate provided with perfora-'tions opposite to the microphone opening but not in line therewith.

5. A telephone transmitter comprising a micro hone having an opening, awrapping theref dr of sound deadening material, an outer case having aface plate provided with perforations opposite to the microphone openingbut not in line therewith and tions of-which are not in line with theperforations in said face plate to the outer case.

7. A telephone transmitter comprising a microphone having an opening, awrapping therefor completely inclosing the same of sound deadeningmaterial, an outer case having a perforated face plate opposite to themicrophone opening, a protecting cap on the rear of said case and soundinsulating material within said case.

8. A telephone transmitter comprising a microphone having an opening, awrappmg of sound deadening material therefor, an outer case having aperforated face plate opposite the microphone opening, a cover having aperforated face plate opposite to and spaced *fromthe face plate of thecase and a flexible mouth piece provided with an inner edge extendingover that portion of the face plate of the cover adjacent to its edge.

9. A telephone transmitter comprising a microphone having an opening, awrapping therefor of sound deadening material, an outer case havin aperforated face plate opposite to the mlcrophone opening, a back cap onthe rear of the outer case, sound insulating material within said cap, acover.

having an apertured face plate opposite to andspaced from the faceplateof the case and a flexible mouth piece secured to the cover. i

10. A telephone transmitter comprising a microphone, a wrapping thereforcompletely inclosing the same of sound deadening material, an outer casehaving a perforated faceplate opposite to the microphone opening andmeans for varying the size of said 105 perforations.

In testimony whereof Ihave aflixed' my signature.

STEPHEN C. PORTER

